This invention relates to a tablet selector, and more particularly to an apparatus for selecting tablets according to the diameter of the tablets.
Throughout the specification and the appended claims, the term "reject tablet" means a tablet having a diameter smaller than the specified diameter, and the term "acceptable tablet" means a tablet other than the reject tablet.
Generally the tablets to be separated for selection include up to about 50 to 60 reject tablets per 300,000 tablets. Apparatus for separating off such reject tablets heretofore known comprise a square perforated plate disposed in a substantially inclined position and a vibrator for vibrating the perforated plate. With the known apparatus, the tablets fed to the upper end of the perforated plate for separation are moved progressively downward to its lower end, while allowing reject tablets to fall through perforations formed in the plate. The apparatus, however, have the drawback of involving extreme difficulty in adjusting the vibration to be given to the perforated plate. If the vibration of the perforated plate is too small, acceptable tablets will clog some perforations with their lower half portions and be held engaged therein, thus hindering separation of other tablets, whereas the perforated plate, if vibrated to excess, will permit the tablets to rapidly descend the sloping surface of the perforated plate and reach its lower end without allowing the reject tablets to fall through the perforations.